A Case of Cutaneous Mastocytosis in a Child with Prominent Langerhans Cell Infiltration

Abstract

We recently encountered a 2-year-old boy with slightly infiltrative brown papules on the face, trunk, and extremities. Stroking of one of the papules produced an urticarial wheal (positive Darier's sign). Histopathologic tests revealed a dense infiltration of mast cells containing numerous granules and showing metachromasia under Toluidine blue staining. Immunohistochemical tests revealed that these cells were positive for CD68 and for c-kit. In addition, dermal dendritic cells that were positive for S100 and CD1a immunostaining were intermingled with the mast cells. We confirmed through electron microscopy that the dermal dendritic cells that were observed adjacent to the infiltration of mast cells had Birbeck granules in their cytoplasm, namely Langerhans cells. However, because of the greater numbers of mast cells than Langerhans cells, and because of the absence of both monomorphic LC proliferation and systemic symptoms of Langerhans cell histiocytosis, the present case favors a diagnosis of cutaneous mastocytosis in a child with Langerhans cell infiltration.

CD1a-positive familial cutaneous mastocytosis without germ-line or somatic mutations in c-kit

“…One was a 2‐year‐old boy with multiple red‐brown maculopapular lesions with positive Darier sign. In this case, spindle MCs infiltrated interstitially into the upper dermis accompanied by less frequent S‐100 + CD1a + histiocytes . The other case was an 11‐year‐old girl with brown macules and a nodule infiltrated predominantly by MCs in the presence of xanthomatous histiocytes .…”

“…6 In contrast, a MC-rich variant of histiocyosis X was reported as self-healing histiocytosis, or urticating Hashimoto-Pritzker disease. 5 These observations suggest that mastocytosis and LCH could coexist within the skin. CD1d expressed on MCs have been reported to be involved in mast cell increase via CD1d-restricted NKT cells.…”

“…The other case was an 11‐year‐old girl with brown macules and a nodule infiltrated predominantly by MCs in the presence of xanthomatous histiocytes . In contrast, a MC‐rich variant of histiocyosis X was reported as self‐healing histiocytosis, or urticating Hashimoto–Pritzker disease . These observations suggest that mastocytosis and LCH could coexist within the skin.…”

“…In this case, spindle MCs infiltrated interstitially into the upper dermis accompanied by less frequent S-100 + CD1a + histiocytes. 5 The other case was an 11-year-old girl with brown macules and a nodule infiltrated predominantly by MCs in the presence of xanthomatous histiocytes. 6 In contrast, a MC-rich variant of histiocyosis X was reported as self-healing histiocytosis, or urticating Hashimoto-Pritzker disease.…”

Cutaneous Mastocytosis With Significant Langerhans Cell Infiltration. A Case Report

“…The Darier's sign, a characteristic feature of mastocytosis, can be a clue for the differential diagnosis of these diseases. Only four cases characterized by prominent mast and Langerhans cell infiltration in the same biopsy specimen have been reported in the literature (1)(2)(3)(4).…”